8-Mbyte flash problems

I am having a puzzling problem and hope someone can help. We have created
our own dev board which has 64 M of SDRAM and 8 MB of flash (yes I know it's
a lot of memory but it's a dev board right now..). The flash is an AMD
29LV641DH which is a 4M x 16 part.
Before I changed anything related to size I verified that the board works
fine with the ptablespec still setup like the dev board with a 2M part. This
works great, board boots, part flashes fine and runs. I then updated the
flash2 size in ptablespec file as follows:
[ptable]
# name size rw-options type image-file
rescue 0x010000 ro rescue rescue.img
flash1 0x1a0000 ro kernel flash1.img
#flash2 0x050000 rw jffs flash2.img --> original 2M size
flash2 0x650000 rw jffs flash2.img
and tried flashing the board using the command:
$ ./flashitall -S 8
The bootloader seems to be OK for a while until it hits the 4M address and
then gets verify errors for anything after that point. Here's the debug port
information:
.
.
.
SET_REGISTER
0xB0000038
0x00001EF3
PACKET_INFO
0xC0004000
0x00800018
Checksum of file is 0x73AC645A
FLASH
0xC0004000
0x00000000
0x00800000
Probing flash...
CFI dev 0x80000000
0x80000000: Erasing 0x00800000 bytes...done, verifying...OK
0x80000000: Writing 0x00800000 bytes...
Verify error at 0x80400000
Verify error at 0x80400002
Verify error at 0x80400004
Verify error at 0x80400004
.
.
.
So it apears that it was able to erase/read all 8M but only able to program
the first 4M.
Any clues? I am at a loss to explain this.
David Kilp